Along with the development of communication infrastructures and progress of information communication technologies, an information service using the Internet can be made. In the information service using the Internet, not only text information but also multimedia information containing an image, audio, and the like can be provided.
Users who receive information services via the Internet can make communication and exchange of information using e-mail messages among users by registering their mail accounts required to use e-mail.
Normally, e-mail information is text. Also, binary files such as application data (document files) and the like created by users can be attached to e-mail information using an encode technique to text data and a decode technique from text data, and can be exchanged among users.
On the other hand, along with the development of communication infrastructures, the progress of information communication technologies, and size reductions of terminals required to use them, connection to the Internet can be established not only from desktop personal computers but also portable terminals for a mobile environment such as portable phones and the like. As a result, users who utilize e-mail via portable terminals are increasing rapidly.
Means that can acquire information distributed on the Internet are not limited to personal computers, but are wide-ranging devices including portable terminals, e-mail dedicated terminals, and the like. For this reason, unique physical and performance limitations such as limitations on the information size that can be received, limitations on display performance of terminals such as the display size, color, resolution, and the like vary. Even in communications or exchange of e-mail messages between personal computers which suffer less limitations, an information processing environment common to both the sender and receiver is often deficient.
In such environment, if the receiver's environment cannot process received information, that information is discarded without being acquired as information. Hence, information to be exchanged may be lost unless information exchange is made after both the environments are confirmed in advance.
For example, portable terminals can exchange e-mail messages via the Internet. However, the number of received characters per mail message, and information contents that can be handled (attachment of computer digital files or binary files) are limited, and information beyond such limitations is discarded. Therefore, information that an e-mail receiver cannot normally receive (which may be discarded before it reaches a terminal) may be generated unless the e-mail receiver informs an e-mail sender of such limitations.
One can imagine from the domain name of a mail address that the destination of information is a portable terminal, but such address makes no difference from that of a standard Internet mail address system. Furthermore, some portable terminal users forward mail messages with mail addresses, which are normally used in terminals with different limitations on e-mail reception performance such as desktop personal computers or the like, to mail addresses of portable terminals. Therefore, the senders cannot easily determine the information reception performance of receivers' terminals. As a result, it is very difficult for an e-mail sender to predict a receiver's environment, and to process information to allow the receiver to receive it upon sending the information.
Therefore, many e-mail messages exchanged via portable terminals currently suffer loss of information.
In order to avoid such problems, a technique for forwarding an e-mail message to a portable terminal to one account on a server that exploits the World Wide Web technique, and browsing that message via a mechanism of the World Wide Web is already available. However, such technique can only avoid a limitation on the number of received characters at a portable terminal, but cannot cope with browsing of binary files and data acquisition. In this arrangement, since an e-mail message to a portable terminal is unconditionally forwarded to a World Wide Web server, the portable terminal user must always check if mail messages have been forwarded to the World Wide Web server, thus imposing a heavy load on the portable terminal user.
When an e-mail sender attaches a document file or the like created using some application to an e-mail message, a user who uses a portable terminal alone as connection means to the Internet can expand the attached file on the portable terminal, but the expanded file often goes beyond the limitations such as display performance or the like of the portable terminal.
Furthermore, not only in a portable terminal but also in an Internet connection terminal such as a desktop personal computer or the like, which suffers less limitations as reception means, a mail receiving terminal must have an application which is the same as that used when an e-mail sender created an attached document, or is compatible to that application, so as to expand and display document information attached to an e-mail message. However, such application is not always present in the e-mail receiving terminal. If the receiver does not have any application which is the same as that used when the sender created an attached document or is compatible to that application, he or she cannot review information sent from the e-mail sender.
In such environment, the receiver cannot confirm information sent from the sender unless he or she prepares for an environment compatible to the sending environment of the sender with much labor.